With the fast development of display technology, touch screen panels have become popular in people's life gradually. At present, according to constitution structure, touch screens may be classified into add-on mode touch panels, on-cell touch panels and in-cell touch panels. For an add-on mode touch panel, the touch panel and the liquid crystal display (LCD) are produced separately and then attached together to form a liquid crystal display with touch function. Add-on mode touch panels have high manufacturing costs, low light transmission rate and great module thickness. While for an in-cell touch panel, touch electrodes of the touch panel are embedded inside the liquid crystal display, which can reduce the overall thickness of the assembly, and can drastically reduce manufacturing costs of the touch panel. Therefore, in-cell touch panels have received great attentions from panel manufacturers.
At present, an in-cell touch panel detects the touch position of a finger based on the mutual capacitance or self-capacitance principle. As for the self-capacitance principle, it is possible to provide a plurality of self-capacitance electrodes disposed in the same layer and insulated from each other in a touch panel. When a human body does not touch the screen, each self-capacitance electrode experiences capacitance of a fixed value. When the human body touches the screen, corresponding self-capacitance electrodes experience capacitance of the fixed value plus the human body capacitance. The touch sensing chip can determine the touch position by detecting the variation of the capacitance value of the self-capacitance electrodes in the touch period. Since the body capacitance can act on all the self-capacitance electrodes, as compared to the situation where the body capacity that can only act on projection capacitance in the mutual capacitance principle, the touch variation caused by the body touching action on the screen would be greater than that of the touch panel manufactured in accordance with the mutual capacitance principle.